A large variety of medical devices exist in the market. Many of these medical devices include the connection of sensors or probes to a host processing system. Examples include ultrasound platforms, ECG machines, critical care monitors, and emergency care monitors. The interfaces for these connections are usually proprietary using different electrical standards, protocols, and connectors.
Some companies produce products with an interface which allows different probes or pods or sensor units to be connected. One example is the range of critical care monitors from Draeger Medical, where various probes or pods can be connected to the monitor. The probes or pods connect to the monitor through a cable providing power and communications. Usually, communications are via a standard interface such as RS232. The critical care monitors can connect to pods or probes such as CO2 monitoring, EEG monitoring, ECG monitoring, blood pressure monitoring, and oxygen saturation monitoring. The data rate required for monitoring all of these conditions is relatively low (orders of Kbytes per second), and adequately served by standard interfaces such as RS232. However, this connection scheme cannot support pod functions requiring higher transfer rates such as ultrasound, or camera based pod functions such as endoscopes.
There are a variety of interfaces used to connect ultrasound probes to host processing systems. The most common interface is an analog interface, where raw analog voltages are transmitted to and from probe ceramics using a cable and connector. The number of channels in most ultrasound systems is very high, resulting in cables and connectors interfacing large numbers of channels. The connectors and interfaces for these ultrasound systems are proprietary, with no industry accepted standard.
A more recent development is where an ultrasound pod connects to an ultrasound probe, and the pod then connects to a host processing system. The link between the pod and the host must support very high data rates, as even a single channel of raw digital data from an ultrasound probe uses a bandwidth which may exceed 300 Mbps. Terason Corporation market such a product, where the pod to host system link is via a Firewire (IEEE1394) interface. Other manufacturers interface to digital probes using USB2.0 interfaces. These standards operate at data rates of up to 480 Mbps.
A significant disadvantage of using a USB2 or a Firewire interface is relatively high power consumption. For example, a standard USB2 host device such as the ISP1760 made by Philips, consumes approximately 254 mW when in operation. A client USB2 device containing a slave USB2 controller such as the ISP1583 consumes about 198 mW in operation. Therefore, the communications overhead for a USB2 device is approximately 452 mW. This power consumption is a significant problem for portable devices reliant on battery power, or other applications where low overall power consumption is important.
The USB mechanical standard does not provide an interface particularly well suited to a handheld or portable medical device. The USB2 standard specifies a maximum extraction force for a USB2 connector to be 10N, and therefore is not suited to being used in handheld devices where large stresses may be place on connectors and cables.
It is an object of the present invention to provide a medical device connector and interface that overcomes or at least substantially ameliorates the problems associated with the prior art.